Electromagnetic relay

Abstract

This electromagnetic relay comprises: an electromagnetic coil (21) that generates a magnetic force by being energized; a first contact part (14); and a second contact part (121) that comes into contact with or separates from the first contact part as the electromagnetic coil is switched between being energized and not being energized, thereby opening / closing an energization path. In addition, the electromagnetic relay also comprises: a case (30) that accommodates the electromagnetic coil, the first contact part, and the second contact part therein; and heat-conducting members (44, 45) disposed outside the case. The heat-conducting members have one surface (441, 451) joined to the case and the other surface (442, 452) provided on the opposite side to the one surface and exposed to a space (30b) around the case, and have a higher thermal conductivity than the case.

Description

Electromagnetic relay Cross-reference to related applications

[0001] This application is based on Japanese Patent Application No. 2024-224161 filed on December 19, 2024, the content of which is incorporated herein by reference.

[0002] This disclosure relates to an electromagnetic relay.

[0003] As this type of electromagnetic relay, for example, an electromagnetic relay described in Patent Document 1 has been conventionally known. The relay described in this Patent Document 1 is mounted on a circuit board, and the circuit board and the relay are housed in an exterior member. And between the case top surface of the relay case and the inner surface of the exterior member, a heat conduction member that contacts the case top surface and the inner surface of the exterior member is disposed. This heat conduction member is made of a rubber-like material or a silicon-based material, has flexibility and surface adhesiveness, and is in a slightly compressed state between the case top surface and the inner surface of the exterior member.

[0004] In a low-temperature environment where condensation can occur, due to the provision of the heat conduction member, the relay top surface is cooled, and thereby, in the relay case, it becomes easier to condense on the inner surface of the relay case. As a result, in the relay case, condensation concentrates on the inner surface of the relay case, so that condensation of the contact portion disposed in the relay case is suppressed. Note that condensation of the contact portion causes poor conduction of the contact portion due to freezing of the condensed moisture in a low-temperature environment.

[0005] Japanese Unexamined Patent Application Publication No. 2017-59693

[0006] In an electromagnetic relay such as the relay of Patent Document 1, a case (for example, the above relay case) forming the outer shell of the electromagnetic relay expands or contracts with temperature changes inside or around the electromagnetic relay. Therefore, the heat conduction member of the relay of Patent Document 1 is formed in a rectangular annular shape or a cylindrical shape with the central portion open. From this, in Patent Document 1, it is said that the heat conduction member is easily compressed and deformed, and breakage of the relay case during thermal expansion can be suppressed.

[0007] However, as can be seen from the fact that the heat conductive member in the relay described in Patent Document 1 is formed in an annular or cylindrical shape, there are significant constraints on the shape of the heat conductive member that enhances the cooling performance of the relay case. For this reason, it was considered necessary to use a different technology from that described in Patent Document 1 to cool the case of the electromagnetic relay, or in other words, a means to keep the case at a low temperature for a long period of time. As a result of detailed investigations by the inventors, the above findings were discovered.

[0008] In view of the above, this disclosure aims to provide an electromagnetic relay that suppresses condensation at the contact points by keeping the case at a low temperature for a long period of time using a heat conductive member, and that can relax the constraints on the shape of the heat conductive member.

[0009] To achieve the above objective, an electromagnetic relay according to one aspect of this disclosure comprises: an electromagnetic coil that generates a magnetic force when energized; a first contact portion; a second contact portion that moves toward and away from the first contact portion in conjunction with the switching of energization and de-energization of the electromagnetic coil, thereby opening and closing the energization path; a case that houses the electromagnetic coil, the first contact portion and the second contact portion inside; and a thermal conductive member disposed on the outside of the case, having one surface joined to the case and the other surface on the opposite side of that surface exposed to the space around the case, and having a higher thermal conductivity than the case.

[0010] In this way, since the other side of the heat conduction member is exposed to the space around the case, even if the case expands due to heat, the heat conduction member does not generate a pressing force that pushes back against the case. Therefore, it is not necessary to impose shape constraints on the heat conduction member, such as those described in Patent Document 1, and the constraints on the shape of the heat conduction member can be relaxed.

[0011] Furthermore, since the thermal conductivity of the heat-conducting material is higher than that of the case, the heat-conducting material exposed to the surrounding space (the space around the case) will reach a temperature similar to that of the surrounding space, not only on the surface facing the surrounding space but throughout its entirety. Therefore, in low-temperature environments where, for example, the temperature inside the case rises due to the heat generated by the electromagnetic coil when current is applied, and condensation due to the generated water vapor is a concern, the heat-conducting material functions like a kind of cold storage material for the case, allowing the case to be kept at a low temperature for a longer period. As a result, condensation concentrates on the inner surface of the case, suppressing condensation at the first and second contact points.

[0012] Furthermore, in the low-temperature environment described above, the air inside the case is also cooled by the heat-conducting material, which reduces the temperature difference between the first and second contact points and the air surrounding them. This also helps to suppress condensation at the first and second contact points.

[0013] This is a longitudinal cross-sectional view showing the schematic configuration of an electromagnetic relay according to the first embodiment, and shows an electromagnetic relay in an unenergized state where the electromagnetic coil is not energized. This is a cross-sectional view showing the section II-II in Figure 1. This is a cross-sectional view showing the section III-III in Figure 1. This is a cross-sectional view showing the section corresponding to the section III-III in Figure 1 in the second embodiment, and corresponds to Figure 3. This is a cross-sectional view showing the section corresponding to the section III-III in Figure 1 in the third embodiment, and corresponds to Figure 3. This is a cross-sectional view showing the section corresponding to the section III-III in Figure 1 in the fourth embodiment, and corresponds to Figure 3.

[0014] The embodiments will be described below with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other are denoted by the same reference numerals in the drawings.

[0015] (First Embodiment) The electromagnetic relay 10 of this embodiment is mounted on a vehicle, for example, and opens and closes the power supply path to vehicle components by switching between the energized state and the de-energized state of the electromagnetic coil 21. The energized state of the electromagnetic coil 21 is the state in which the electromagnetic coil 21 is energized, and the de-energized state of the electromagnetic coil 21 is the state in which the electromagnetic coil 21 is not energized. The electromagnetic relay 10 is also called a relay device.

[0016] In this embodiment, the equipment axis CL shown in Figure 1 may be used to represent the structure of the electromagnetic relay 10. The axial direction of the equipment axis CL may be referred to as the equipment axis direction Da, and corresponds to one direction in this disclosure. Furthermore, when the electromagnetic relay 10 is mounted on a vehicle, it is positioned so that the equipment axis direction Da is perpendicular to the vertical direction Dg. In Figure 1, the right side of the paper represents one side of the equipment axis direction Da, and the left side of the paper represents the other side opposite to the one side of the equipment axis direction Da. The upper and lower sides of the vertical direction Dg in the vehicle-mounted state of the electromagnetic relay 10 are indicated by arrows in Figures 2 and 3.

[0017] Furthermore, the radial direction of the machine axis CL is sometimes referred to as the machine radial direction Dr. This machine radial direction Dr is the direction that is perpendicular to the machine axis CL while moving away from it. In other words, the machine radial direction Dr is the radial direction of a circle drawn in a virtual plane centered on the intersection of a virtual plane perpendicular to the machine axis CL and the machine axis CL itself.

[0018] As shown in Figures 1 to 3, the electromagnetic relay 10 of this embodiment comprises a movable element 12, a plurality of fixed contact parts 14, a plurality of fixed busbars 141, a plunger 16, a solenoid part 20, a case 30, a movable element biasing member 32, a core biasing member 34, a pair of arc-extinguishing magnets 36, a case internal member 40 on one side, a case internal member 41 on the other side, and a heat conducting member 44.

[0019] The solenoid unit 20 reciprocates the plunger 16 in the machine axis direction Da by the magnetic force generated by the electromagnetic coil 21 contained in the solenoid unit 20. The movable element 12 has a movable contact portion 121 that moves toward and toward the fixed contact portion 14. The plunger 16 reciprocates the movable element 12 in the machine axis direction Da such that the fixed contact portion 14 and the movable contact portion 121 move toward and away from each other. The same number of movable contact portions 121 are provided as the number of fixed contact portions 14. In this embodiment, the fixed contact portion 14 corresponds to the first contact portion of this disclosure, and the movable contact portion 121 corresponds to the second contact portion of this disclosure.

[0020] The solenoid unit 20 includes an electromagnetic coil 21, a movable core 22, a one-side yoke 23, a fixed core 24, a other-side yoke 25, and a bobbin 26. The electromagnetic coil 21, the one-side yoke 23, the fixed core 24, the other-side yoke 25, and the bobbin 26 are fixed to the case 30. The electromagnetic coil 21 forms a magnetic flux when energized. The movable core 22 is reciprocated in the axial direction Da of the equipment as the energization of the electromagnetic coil 21 is switched between energized and de-energized.

[0021] The case 30 is a housing that constitutes the outer shell of the electromagnetic relay 10 and is made of an insulating material. The case 30 in this embodiment is formed in a substantially rectangular parallelepiped shape with an internal space. For example, the case 30 in this embodiment is made of a resin such as PBT or LCP. PBT is an abbreviation for Polybutylene terephthalate, and LCP is an abbreviation for Liquid Crystal Polymer.

[0022] The internal space 30a of the case 30 houses the movable element 12, the fixed contact part 14, the plunger 16, the solenoid part 20, the movable element biasing member 32, the core biasing member 34, the arc extinguishing magnet 36, the internal case member 40 on one side, and the internal case member 41 on the other side. For example, the case 30 includes a plurality of resin parts, and these plurality of resin parts are connected to each other.

[0023] Furthermore, both the multiple fixed contact portions 14 and the multiple movable contact portions 121 of the movable element 12 are arranged biased to one side in the axial direction Da of the equipment within the case 30. In contrast, the solenoid portion 20, including the electromagnetic coil 21, is arranged biased to the other side in the axial direction Da of the equipment within the case 30.

[0024] The inner case member 40 on one side and the inner case member 41 on the other side are each made of an insulating material such as resin and are fixed to the case 30. Within the case 30, the inner case member 41 on the other side is positioned on the opposite side of the inner case member 40 in the direction of the equipment axis Da. The inner case member 40 on one side and the inner case member 41 on the other side are connected to each other, forming a structure that surrounds the movable element 12 and the multiple fixed contact parts 14.

[0025] The movable element 12 has a plurality of movable contact portions 121, as well as a movable conductor 122 and a spring seat 123. The movable conductor 122 is made of a metal plate-shaped member that is conductive and has its thickness in the direction of the equipment axial direction Da. For example, the movable conductor 122 is made of copper or a copper alloy.

[0026] Furthermore, the movable conductor 122 extends in the axial perpendicular direction Db, which is perpendicular to the vertical direction Dg and the machine axis direction Da, and movable contact portions 121 are fixed to the vicinity of both ends of the movable conductor 122 in the axial perpendicular direction Db. For example, the movable contact portions 121 are fixed to the movable conductor 122 by crimping. As described above, the movable conductor 122 is a conductive metal member, so the multiple movable contact portions 121 of the movable element 12 are electrically connected to each other via the movable conductor 122.

[0027] The spring seat 123 of the movable element 12 is fixed to the movable conductor 122 and is interposed between the movable conductor 122 and the movable element biasing member 32. The movable contact portion 121, the movable conductor 122, and the spring seat 123 that constitute the movable element 12 are integrally fixed to each other.

[0028] The movable element biasing member 32 is a compression coil spring wound around the machine axis CL and expanding and contracting in the machine axis direction Da. The movable element biasing member 32 is positioned between a wall portion of the inner case member 40 located on one side in the machine axis direction Da relative to the movable conductor 122 and a spring seat 123. The movable element biasing member 32 contacts the aforementioned wall portion of the inner case member 40 at one end and contacts the spring seat 123 at the other end. As a result, the movable element biasing member 32 is compressed in the machine axis direction Da, biasing the movable element 12 to the other side in the machine axis direction Da.

[0029] The multiple fixed contact portions 14 and the multiple movable contact portions 121 are made of a conductive material with high arc resistance. The multiple fixed contact portions 14 are positioned on the other side of the equipment axial direction Da relative to the multiple movable contact portions 121, and are facing each of the multiple movable contact portions 121 in the equipment axial direction Da.

[0030] In detail, each of the multiple fixed contact portions 14 has a fixed contact surface 14a that faces the movable contact portion 121 and is oriented toward one side in the machine axis direction Da. Each of the multiple movable contact portions 121 has a movable contact surface 121a that faces the other side in the machine axis direction Da and is oriented toward the fixed contact surface 14a and moves toward and toward it. As can be seen from this configuration, the movement of the movable contact portion 121 toward and toward the fixed contact portion 14 is equivalent to the movement of the movable contact surface 121a toward and toward the fixed contact surface 14a. In this embodiment, the fixed contact surface 14a corresponds to the first contact surface of this disclosure, and the movable contact surface 121a corresponds to the second contact surface of this disclosure.

[0031] Specifically, there are two fixed busbars 141, and they are made of conductive metal plate-like members. For example, the fixed busbars 141 are made of copper or a copper alloy. Each of the fixed contact portions 14 is fixed to the fixed busbars 141, for example, by crimping. In this way, each of the fixed contact portions 14 is electrically connected to the fixed busbar 141 to which the fixed contact portion 14 is crimped.

[0032] Furthermore, each of the fixed busbars 141, specifically the contact fixing portion to which the fixed contact portion 14 is crimped and fixed, is positioned on one side in the axial direction Da relative to the other side case internal member 41, and is fixed and supported by the other side case internal member 41. In other words, each of the multiple fixed contact portions 14 is fixed to the case 30 via the fixed busbar 141 and the other side case internal member 41.

[0033] In each fixed busbar 141, a portion of the fixed busbar 141 protrudes to the outside of the case 30, and these protruding portions each serve as connection terminals 141b that are connected to external wiring, etc. Specifically, each connection terminal 141b protrudes downward in the vertical direction Dg from the case 30. At the base end portion of these connection terminals 141b on the case 30 side, multiple fixed busbars 141 are fixed to the case 30.

[0034] Furthermore, the other side case internal member 41 has a through hole 41a that penetrates the other side case internal member 41 in the equipment axial direction Da, and a part of the plunger 16 is inserted through this through hole 41a. A small radial gap is formed between the inner wall surface of the through hole 41a of the other side case internal member 41 and the plunger 16, and this radial gap allows the plunger 16 to move in the equipment axial direction Da without contacting the other side case internal member 41. The above-mentioned radial gap is a gap that opens in the equipment radial direction Dr.

[0035] For example, when the plunger 16 moves to one side in the machine axis direction Da and pushes the movable element 12, the movable element 12 moves together with the plunger 16 to one side in the machine axis direction Da, against the biasing force of the movable element biasing member 32, due to being pushed by the plunger 16 in this way. As a result, the movable contact portion 121 moves away from the fixed contact portion 14. Also, when the plunger 16 moves to the other side in the machine axis direction Da, the biasing force of the movable element biasing member 32 causes the movable contact portion 121 to move to the other side in the machine axis direction Da until it contacts the fixed contact portion 14 and is pressed against the fixed contact portion 14. The plunger 16 is configured to reciprocate in the machine axis direction Da in response to the operation of the solenoid portion 20.

[0036] When current is passed through the electromagnetic coil 21, a magnetic flux is formed in the magnetic path composed of the fixed core 24, the movable core 22, the one-sided yoke 23, and the other-sided yoke 25, thereby generating a magnetic force.

[0037] The electromagnetic coil 21 is composed of a wire, or winding, wound around the outer circumference of a cylindrical portion 261 of a bobbin 26. The surface of the wire wound around the cylindrical portion 261 is covered with an insulating resin film. The bobbin 26 is also made of an insulating material such as resin. Since the cylindrical portion 261 of the bobbin 26 is formed in a cylindrical shape centered on the machine axis CL, the electromagnetic coil 21 is also formed in a cylindrical shape centered on the machine axis CL.

[0038] A through-hole is formed inside the cylindrical portion 261 of the bobbin 26, extending in the direction of the machine axis Da. Thus, the cylindrical portion 261 opens to one side and the other side in the direction of the machine axis Da. Inside the cylindrical portion 261, a part of the plunger 16, a fixed core 24, and a core biasing member 34 are arranged.

[0039] Furthermore, the cylindrical portion 261 has a cylindrical shape in which one side in the direction of the machine axis Da gradually widens in diameter compared to the other side. At the point where the diameter of the cylindrical shape changes, the cylindrical portion 261 has a contact surface 261a facing one side in the direction of the machine axis Da. The core biasing member 34 is in contact with this contact surface 261a.

[0040] The movable core 22 and the fixed core 24 are made of a soft magnetic metal such as iron. The fixed core 24 is positioned inside the electromagnetic coil 21 via the cylindrical portion 261 of the bobbin 26. The movable core 22 and the fixed core 24 are each formed around the machine axis CL. For example, the movable core 22 and the fixed core 24 each have a rotating body shape or a substantially rotating body shape around the machine axis CL.

[0041] The fixed core 24 is located on the other side of the movable core 22 in the machine axis direction Da, and is positioned opposite to the machine axis direction Da. The fixed core 24 is also fixed to the other side yoke 25 by crimping at the other end in the machine axis direction Da.

[0042] Inside the fixed core 24, a guide hole 24a is formed that penetrates the fixed core 24 in the device axis direction Da and is centered on the device axis CL. The shaft portion 161 of the plunger 16 is inserted into this guide hole 24a. The shaft portion 161 of the plunger 16 inserted into the guide hole 24a is movable relative to the fixed core 24 in the device axis direction Da, and the fixed core 24 guides the shaft portion 161 of the plunger 16 that reciprocates in the device axis direction Da through the guide hole 24a.

[0043] The movable core 22 has a substantially disk shape that spreads out to cover the fixed core 24 on one side of the fixed core 24 in the device axis direction Da. Also, the shaft portion 161 of the plunger 16 penetrates the movable core 22, and the movable core 22 is fixed to the shaft portion 161 of the plunger 16. Therefore, the plunger 16 and the movable core 22 move integrally.

[0044] The core biasing member 34 is a compression coil spring wound around the device axis CL and expanding and contracting in the device axis direction Da. The core biasing member 34 is disposed inside the cylindrical portion 261 of the bobbin 26 and outside the fixed core 24 in the device radial direction Dr.

[0045] Also, the core biasing member 34 contacts the movable core 22 at one end on one side of the core biasing member 34 in the device axis direction Da and contacts the contact surface 261a of the bobbin 26 at the other end on the other side of the device axis direction Da. In short, the core biasing member 34 is disposed between the movable core 22 and the contact surface 261a of the bobbin 26 in the device axis direction Da. With such an arrangement, the core biasing member 34 is compressed in the device axis direction Da, and biases the movable core 22 and the plunger 16 fixed to the movable core 22 toward one side in the device axis direction Da. In other words, the core biasing member 34 biases the movable core 22 away from the fixed core 24 toward one side in the device axis direction Da.

[0046] The one-side yoke 23 and the other-side yoke 25 are each made of a soft magnetic metal such as iron, which is suitable for forming a magnetic path. The one-side yoke 23 and the other-side yoke 25 are connected to each other, and an electromagnetic coil 21 and a bobbin 26 are accommodated in a space surrounded by the one-side yoke 23 and the other-side yoke 25. That is, the one-side yoke 23 and the other-side yoke 25 function as a yoke formed around the electromagnetic coil 21 as a whole.

[0047] The one-side yoke 23 is arranged on one side of the device axis direction Da with respect to the other-side yoke 25. Also, the one-side yoke 23 is arranged on one side of the device axis direction Da with respect to the electromagnetic coil 21 and the bobbin 26, and is formed so as to overlap the electromagnetic coil 21 and the bobbin 26 on one side of the device axis direction Da.

[0048] The other-side yoke 25 has a bottomed cylindrical shape with a bottom on the other side of the device axis direction Da centered on the device axis CL, and is provided from the radially outer side with respect to the electromagnetic coil 21 and the bobbin 26 to the other side of the device axis direction Da. A through hole is formed in the bottom portion of the bottomed cylindrical shape of the other-side yoke 25, and the fixed core 24 is fixed to the other-side yoke 25 by being caulked in the through hole of the other-side yoke 25.

[0049] The one-side yoke 23 forms a circular hole in the central portion, is connected to the end portion on one side of the other-side yoke 25 in the device axis direction Da at the edge portion, and is fixed to the other-side yoke 25. Also, a through hole penetrating the one-side yoke 23 in the device axis direction Da is formed in the center of the one-side yoke 23, and a part of the movable core 22 enters the inside of the through hole. And at the other-side stroke end position where the shaft portion 161 coupled to the movable core 22 moves to the other side in the device axis direction Da until it abuts against the fixed core 24, the movable core 22 is positioned so as to block the through hole of the one-side yoke 23 from one side in the device axis direction Da.

[0050] The plunger 16 has a shaft portion 161 and an insulator portion 162. The shaft portion 161 and the insulator portion 162 are fixed to each other. The shaft portion 161 of the plunger 16 may be made of resin, but in this embodiment it is made of a non-magnetic metal such as non-magnetic stainless steel.

[0051] The shaft portion 161 of the plunger 16 is formed in a cylindrical shape centered on the machine axis CL. Therefore, the shaft portion 161 is arranged coaxially with the movable core 22 and the fixed core 24.

[0052] Since the plunger 16 and the movable core 22 are fixed to each other, they are moved back and forth along the machine axis direction Da within a predetermined stroke range when the electromagnetic coil 21 is switched between energized and de-energized. Figure 1 shows the plunger 16 and the movable core 22 having moved to the one-side stroke end position, which is the stroke end position on one side of the machine axis direction Da within that stroke range. In this embodiment, the other stroke end position on the machine axis direction Da within the stroke range of the plunger 16 and the movable core 22 is referred to as the other-side stroke end position.

[0053] For example, when the electromagnetic coil 21 is energized, the plunger 16 and the movable core 22 are moved to the other side in the machine axis direction Da by the magnetic force generated by the electromagnetic coil 21, and the shaft portion 161 connected to the movable core 22 abuts against the fixed core 24 and stops. The position in the machine axis direction Da where the shaft portion 161 connected to the movable core 22 abuts against the fixed core 24 is the other side stroke end position of the plunger 16 and the movable core 22. Conversely, when the power to the electromagnetic coil 21 is cut off, the plunger 16 and the movable core 22 are moved to one side in the machine axis direction Da by the biasing force of the core biasing member 34, and stop at the one side stroke end position by abutting against a stopper (not shown), etc.

[0054] The insulator portion 162 of the plunger 16 is provided so as to be coaxial with the shaft portion 161 and is positioned on one side of the shaft portion 161 in the axial direction Da of the equipment. The insulator portion 162 is made of an insulating material such as resin.

[0055] Furthermore, the insulator portion 162 is positioned on the other side of the movable conductor 122 in the machine axis direction Da. Due to this arrangement, when the plunger 16 is moved to one side in the machine axis direction Da, the insulator portion 162 comes into contact with the movable conductor 122 of the movable element 12, pushing the movable element 12 to one side in the machine axis direction Da.

[0056] The heat conduction member 44 is provided to cool the case 30 in low-temperature environments such as cold regions. The heat conduction member 44 is made of a metal such as iron, copper, iron alloy, or copper alloy. Therefore, the thermal conductivity of the heat conduction member 44 is higher than that of the case 30.

[0057] The heat conductive member 44 is positioned on the outside of the case 30 and is joined to the outer surface of the case 30 by adhesive or attachment. In this embodiment, the heat conductive member 44 is joined to the top surface 301 of the case 30. The top surface 301 of the case 30 is located on the upper side of the case 30 in the vertical direction Dg and is formed as a surface facing upward in the vertical direction Dg. That is, the top surface 301 of the case 30 is formed on the side of the case 30 opposite to the side from which the connection terminal 141b of the fixed busbar 141 protrudes.

[0058] Specifically, the heat conduction member 44 is formed in a rectangular parallelepiped shape that extends along the top surface 301 of the case. The heat conduction member 44 has one surface 441 formed on the lower side of the vertical direction Dg and facing downwards, and another surface 442 formed on the upper side of the vertical direction Dg and facing upwards. In other words, the other surface 442 of the heat conduction member 44 is provided on the side opposite to the surface 441 of the heat conduction member 44.

[0059] One surface 441 of the heat conduction member 44 faces the top surface 301 of the case and is joined to the top surface 301 of the case. For example, in this embodiment, one surface 441 of the heat conduction member 44 is joined to the top surface 301 over its entire surface or substantially its entire surface. On the other hand, the outer surface of the heat conduction member 44, including the other surface 442 excluding the one surface 441, in other words, the outer surface of the heat conduction member 44 other than the one surface 441, is exposed to the surrounding space 30b, which is the space around the case 30.

[0060] Furthermore, the heat conductive member 44 is joined to the case top surface 301 over substantially the entire surface of the case top surface 301. Therefore, as shown in Figures 2 and 3, when viewed in a direction along the normal direction of one surface 441 of the heat conductive member 44, all of the multiple fixed contact surfaces 14a and multiple movable contact surfaces 121a fall within the range occupied by that one surface 441. In other words, the entire projected image obtained by projecting the fixed contact surfaces 14a and movable contact surfaces 121a onto the one surface 441 along the normal direction of the one surface 441 falls within the one surface 441.

[0061] Furthermore, the same can be said if we focus on each contact portion 14, 121 rather than each contact surface 14a, 121a. That is, when viewed in a direction along the normal direction of one surface 441 of the heat conductive member 44, all of the multiple fixed contact portions 14 and the multiple movable contact portions 121 fall within the range occupied by that one surface 441. In this embodiment, the normal direction of one surface 441 of the heat conductive member 44 is the same direction as the vertical direction Dg.

[0062] Furthermore, since the heat conductive member 44 functions like a type of cold storage material in a low-temperature environment to cool the case 30, it is preferable that the heat capacity per unit volume of the heat conductive member 44 is larger than the heat capacity per unit volume of the case 30.

[0063] Next, the operation of the electromagnetic relay 10 by switching between energizing and de-energizing the electromagnetic coil 21 will be explained.

[0064] First, let's explain the case when the electromagnetic coil 21 is switched from a non-energized state to an energized state. As shown in Figure 1, when the electromagnetic coil 21 is energized in the electromagnetic relay 10, a magnetic flux is formed in the magnetic path composed of the fixed core 24, the movable core 22, the one-sided yoke 23, and the other-sided yoke 25, and a magnetic attractive force is generated between the movable core 22 and the fixed core 24. That is, when the electromagnetic coil 21 is energized, the fixed core 24 acts the magnetic force generated by the electromagnetic coil 21 on the movable core 22 so that the movable core 22 moves to the other side in the machine axis direction Da. As a result, the movable core 22 is attracted to the fixed core 24, and the movable core 22 and the plunger 16 move to the other side in the machine axis direction Da against the biasing force of the core biasing member 34.

[0065] Consequently, the pressure of the plunger 16 on the movable conductor 122 is released, and the movable element 12 moves to the other side in the axial direction Da of the equipment due to the biasing force of the movable element biasing member 32, causing the multiple movable contact portions 121 to contact the multiple fixed contact portions 14, respectively. More specifically, the multiple movable contact surfaces 121a contact the multiple fixed contact surfaces 14a, respectively.

[0066] This creates an energizing path in which one fixed busbar 141, the fixed contact portion 14 fixed to that fixed busbar 141, the movable element 12, the fixed contact portion 14 fixed to the other fixed busbar 141, and the other fixed busbar 141 are connected in series. In other words, the energizing path is closed. Then, current flows through the energizing path. That is, the electromagnetic relay 10 is connected. In this connected state of the electromagnetic relay 10, the insulator portion 162 separates from the movable element 12.

[0067] Next, we will explain the case when the electromagnetic coil 21 is switched from an energized state to an unenergized state. In the electromagnetic relay 10, when the power to the electromagnetic coil 21 is cut off, the magnetic attractive force between the movable core 22 and the fixed core 24 disappears. Here, the core biasing member 34 has a greater biasing force than the movable element biasing member 32. Therefore, when the above magnetic attractive force is absent, the movable core 22 moves to one side in the machine axis direction Da due to the biasing force of the core biasing member 34, and the movable element 12 is pushed to one side in the machine axis direction Da by the plunger 16, moving away from the fixed contact portion 14. In short, as shown in Figure 1, the multiple movable contact portions 121 move away from the multiple fixed contact portions 14 to one side in the machine axis direction Da as the plunger 16 moves to one side in the machine axis direction Da.

[0068] This interrupts the current flow path between one fixed busbar 141 and the other fixed busbar 141 via the movable element 12. In other words, the current flow path is opened. That is, the electromagnetic relay 10 is put into an interrupted state.

[0069] As described above, the multiple movable contacts 121 move in and out of contact with the multiple fixed contacts 14 in accordance with the switching between energizing and de-energizing the electromagnetic coil 21. By moving in and out of contact with the multiple fixed contacts 14, the multiple movable contacts 121 open and close the energizing path formed between one fixed busbar 141 and the other fixed busbar 141 via the movable conductor 122.

[0070] Furthermore, when the electromagnetic relay 10 switches from the connected state to the disconnected state, the electromagnetic relay 10 will not enter the disconnected state while an arc is generated between the movable contact portion 121 and the fixed contact portion 14. Therefore, the electromagnetic relay 10 is equipped with an arc-extinguishing magnet 36, which is a permanent magnet, to quickly extinguish the arc.

[0071] These arc-extinguishing magnets 36 are arranged in pairs in the direction Db perpendicular to the axis and are fixed to the internal case member 40 on one side. Between the pair of arc-extinguishing magnets 36, a plurality of movable contact parts 121 and a plurality of fixed contact parts 14 are arranged. With this arrangement, the arc-extinguishing magnets 36 extinguish the arc generated between the movable contact parts 121 and the fixed contact parts 14 by stretching it in a direction perpendicular to the axial direction Da of the equipment.

[0072] As described above, according to this embodiment, the heat conductive member 44 has one surface 441 and another surface 442 provided on the opposite side of the surface 441, and is positioned on the outside of the case 30. The one surface 441 of the heat conductive member 44 is joined to the case 30, and the other surface 442 is exposed to the surrounding space 30b, which is the space around the case 30.

[0073] Since the other surface 442 of the heat conduction member 44 is exposed to the surrounding space 30b, even if the case 30 expands due to heat, the heat conduction member 44 does not generate any pressing force against the case 30 that pushes it back. Therefore, there is no need to impose shape constraints on the heat conduction member 44, such as those described in Patent Document 1, and the constraints on the shape of the heat conduction member 44 can be relaxed.

[0074] For example, there is no need to provide a hole in the heat conduction member 44 of this embodiment, such as the central opening of the heat conduction block described in Patent Document 1. Furthermore, since the heat conduction member 44 of this embodiment is not compressible, the flexibility possessed by the heat conduction block described in Patent Document 1 is also unnecessary for the heat conduction member 44 of this embodiment.

[0075] Furthermore, since the thermal conductivity of the heat conduction member 44 is higher than that of the case 30, the heat conduction member 44 exposed to the surrounding space 30b of the case 30 reaches a temperature similar to that of the surrounding space 30b, not only on the surface portion facing the surrounding space 30b but throughout its entirety. Therefore, in a low-temperature environment where, for example, the temperature inside the case 30 rises due to the heat generated by the electromagnetic coil 21 when energized, and condensation may occur due to the generated water vapor, the heat conduction member 44 functions like a kind of cold storage material for the case 30, allowing the case 30 to be kept at a low temperature for a longer period. As a result, condensation concentrates on the inner surface 302 of the case 30, suppressing condensation on the fixed contact portion 14 and the movable contact portion 121. Note that arrow A1 in Figure 3 schematically represents the transfer of heat from the case 30 and the internal space 30a of the case to the surrounding space 30b, which is a low-temperature environment surrounding the case 30, via the heat conduction member 44.

[0076] Furthermore, in the low-temperature environment described above, the air in the case cavity 30a is also cooled by the heat conductive member 44, which reduces the temperature difference between the fixed contact portion 14 and the movable contact portion 121 and the air surrounding these contact portions 14 and 121. This also helps to suppress condensation on the fixed contact portion 14 and the movable contact portion 121.

[0077] As a result, when the electromagnetic relay 10 is used in a cold region where the temperature may fall below freezing, it is possible to avoid poor conductivity between the contact parts 14 and 121 caused by the freezing of moisture condensed on each contact surface 14a and 121a.

[0078] (1) Furthermore, according to this embodiment, as shown in Figures 2 and 3, when viewed in a direction along the normal direction of one surface 441 of the heat conductive member 44, the fixed contact surface 14a and the movable contact surface 121a fall within the range occupied by that surface 441. As a result, the part of the case 30 to which the heat conductive member 44 is joined is positioned to a certain extent close to each contact surface 14a and 121a, so that the air around each contact surface 14a and 121a in the case interior space 30a is more easily cooled by the heat conductive member 44. As a result, it is possible to enhance the effect of suppressing condensation on each contact surface 14a and 121a.

[0079] (2) Furthermore, according to this embodiment, it is preferable that the heat capacity per unit volume of the heat conduction member 44 is larger than the heat capacity per unit volume of the case 30. In this way, the heat conduction member 44 functions like a kind of cold storage material in a low-temperature environment and cools the case 30, so that the cooling performance of the heat conduction member 44 in cooling the case 30 can be improved while suppressing an increase in the size of the electromagnetic relay 10.

[0080] (Second Embodiment) Next, a second embodiment will be described. In this embodiment, the differences from the first embodiment described above will be mainly explained. Also, parts that are the same as or equivalent to the above embodiment will be omitted or simplified in the explanation. The same applies to the descriptions of the embodiments described later.

[0081] As shown in Figure 4, the heat conduction member 44 of this embodiment is formed in a rectangular parallelepiped shape that expands along the top surface 301 of the case, similar to the first embodiment. However, in this embodiment, the size of the heat conduction member 44 is smaller than that of the first embodiment. Specifically, in the heat conduction member 44 of this embodiment, the width Db in the direction perpendicular to the axis is the same as in the first embodiment, as shown in Figure 2, and extends to almost the entire width of the top surface 301 of the case. In contrast, in the heat conduction member 44 of this embodiment, the width Da in the direction axial of the equipment is shorter than that of the first embodiment, as shown in Figure 4.

[0082] In detail, the heat conduction member 44 in this embodiment does not extend to the entire surface of the case top surface 301 to which the heat conduction member 44 is joined, but is positioned biased to one side in the machine axis direction Da relative to the case 30. In other words, the heat conduction member 44 is positioned biased to one side in the machine axis direction Da of the case top surface 301 to which the heat conduction member 44 is joined. In this embodiment as in the first embodiment, for example, one surface 441 of the heat conduction member 44 is joined to the case top surface 301 over its entire surface or substantially its entire surface.

[0083] As shown in Figures 2 and 4, in a view along the normal direction of one surface 441 of the heat conductive member 44, in this embodiment, as in the first embodiment, all of the multiple fixed contact surfaces 14a and the multiple movable contact surfaces 121a fall within the range occupied by that one surface 441.

[0084] (1) As described above, according to this embodiment, the plurality of fixed contact portions 14 and the plurality of movable contact portions 121 are all arranged biased to one side in the equipment axial direction Da within the case 30, and the electromagnetic coil 21 is arranged biased to the other side in the equipment axial direction Da within the case 30. The heat conducting member 44 is also arranged biased to one side in the equipment axial direction Da with respect to the case 30.

[0085] Therefore, the heat conduction member 44 is positioned away from the electromagnetic coil 21 while being close to the fixed contact portion 14 and the movable contact portion 121. As a result, it is possible to cool the air around the fixed contact portion 14 and the movable contact portion 121 in the case interior space 30a by the heat conduction member 44, while suppressing the heat absorption of the heat conduction member 44 from the electromagnetic coil 21 which generates heat when energized. In other words, it is possible to suppress the reduction in the cooling performance of the heat conduction member 44 in cooling the air around the contact portions 14 and 121 due to heat absorption of the heat conduction member 44 from the electromagnetic coil 21.

[0086] Except as described above, this embodiment is the same as the first embodiment. In this embodiment, the effects obtained from the configuration common to the first embodiment can be obtained in the same way as in the first embodiment.

[0087] (Third Embodiment) Next, a third embodiment will be described. In this embodiment, the differences from the second embodiment described above will be mainly explained.

[0088] As shown in Figure 5, in this embodiment, multiple heat conduction members 44 and 45 are provided. Specifically, two heat conduction members 44 and 45 are provided. One of the two heat conduction members 44 is the same as the heat conduction member 44 of the second embodiment, while the other heat conduction member 45 has a different arrangement than the heat conduction member 44 of the second embodiment. That is, the electromagnetic relay 10 of this embodiment has a configuration in which the other heat conduction member 45 is added to the heat conduction member 44 of the second embodiment, compared to the second embodiment. In this embodiment, for the sake of clarity, the one heat conduction member 44 that is the same as the heat conduction member 44 of the second embodiment is referred to as the first heat conduction member 44, and the other heat conduction member 45 is referred to as the second heat conduction member 45.

[0089] The second heat conduction member 45 differs from the first heat conduction member 44 in its size and arrangement relative to the case 30, but is otherwise similar to the first heat conduction member 44. Therefore, for example, since the second heat conduction member 45 is made of the same material as the first heat conduction member 44, the thermal conductivity of the second heat conduction member 45 is higher than that of the case 30. The second heat conduction member 45 is formed in a rectangular parallelepiped shape and has one surface 451 corresponding to one surface 441 of the first heat conduction member 44 and another surface 452 corresponding to the other surface 442 of the first heat conduction member 44. The one surface 451 of the second heat conduction member 45 is joined to the top surface 301 of the case, and the outer surface of the second heat conduction member 45, including the other surface 452, is exposed to the surrounding space 30b of the case 30. Although the size of the second heat conduction member 45 differs from that of the first heat conduction member 44 in this embodiment, it may be the same.

[0090] As described above, the second heat conduction member 45 has many parts in common with the first heat conduction member 44, but in this embodiment, the second heat conduction member 45 is positioned on the other side of the equipment axial direction Da relative to the first heat conduction member 44. Furthermore, the second heat conduction member 45 is positioned at a distance from the first heat conduction member 44 in the equipment axial direction Da.

[0091] Furthermore, when viewed in a direction along the normal direction of one surface 451 of the second heat conduction member 45, the electromagnetic coil 21 overlaps with the one surface 451 of the second heat conduction member 45. In other words, at least a portion of the projected image obtained by projecting the electromagnetic coil 21 onto the one surface 451 along the normal direction of the one surface 451 overlaps with the one surface 451. In this embodiment, since one surface 451 of the second heat conduction member 45 and one surface 441 of the first heat conduction member 44 are on the same plane, the normal direction of one surface 451 of the second heat conduction member 45 is the same direction as the vertical direction Dg.

[0092] (1) As described above, according to this embodiment, the plurality of fixed contact portions 14 and the plurality of movable contact portions 121 are all arranged biased to one side in the machine axis direction Da within the case 30, and the electromagnetic coil 21 is arranged biased to the other side in the machine axis direction Da within the case 30. The first heat conductive member 44 is arranged biased to one side in the machine axis direction Da with respect to the case 30. In contrast, the second heat conductive member 45 is separated from the first heat conductive member 44 and is arranged on the other side in the machine axis direction Da with respect to the first heat conductive member 44.

[0093] Therefore, the second heat conduction member 45 is positioned to receive heat more easily from the electromagnetic coil 21, which generates heat when energized, than the first heat conduction member 44. As a result, the cooling action of the second heat conduction member 45 suppresses the heat received by the first heat conduction member 44 from the electromagnetic coil 21, while the first heat conduction member 44 can cool the air around the fixed contact portion 14 and the movable contact portion 121 in the internal space 30a of the case. In other words, the cooling performance of the first heat conduction member 44 in cooling the air around the contact portions 14 and 121 is reduced more effectively than when the second heat conduction member 45 is absent, as the reduction in cooling performance due to heat received by the first heat conduction member 44 from the electromagnetic coil 21 is minimized.

[0094] In Figure 5, arrow A1 schematically represents the transfer of heat from the case 30 and the internal space 30a to the surrounding space 30b via the first heat conduction member 44. Arrow A2 schematically represents the transfer of heat from the case 30 and the internal space 30a to the surrounding space 30b via the second heat conduction member 45.

[0095] Except as described above, this embodiment is the same as the second embodiment. In this embodiment, the effects obtained from the configuration common to the second embodiment can be obtained in the same way as in the second embodiment.

[0096] (Fourth Embodiment) Next, a fourth embodiment will be described. In this embodiment, the differences from the first embodiment described above will be mainly explained.

[0097] As shown in Figure 6, in this embodiment, among the multiple resin parts constituting the case 30, the resin part to which the heat conductive member 44 is joined is insert-molded with the heat conductive member 44 as an insert part. Through this insert molding, the heat conductive member 44 is joined to the case 30.

[0098] Except as described above, this embodiment is the same as the first embodiment. In this embodiment, the effects obtained from the configuration common to the first embodiment can be obtained in the same way as in the first embodiment.

[0099] Although this embodiment is a modification based on the first embodiment, it is also possible to combine this embodiment with the second or third embodiment described above.

[0100] (Other Embodiments) (1) In each of the embodiments described above, the heat conductive member 44 shown in Figure 3 is made of metal, for example, but this is just one example. For example, the heat conductive member 44 may be made of a resin material or a gel, as long as the thermal conductivity of the heat conductive member 44 is higher than the thermal conductivity of the case 30.

[0101] (2) In the embodiments described above, the fixed contact portion 14 shown in Figure 1 corresponds to the first contact portion of the present disclosure, and the movable contact portion 121 corresponds to the second contact portion of the present disclosure. However, this is merely an example. For example, the opposite may also be true: the movable contact portion 121 corresponds to the first contact portion of the present disclosure, and the fixed contact portion 14 corresponds to the second contact portion of the present disclosure. In that case, the movable contact surface 121a corresponds to the first contact surface of the present disclosure, and the fixed contact surface 14a corresponds to the second contact surface of the present disclosure.

[0102] (3) In each of the embodiments described above, as shown in Figure 3, the heat conductive member 44 is joined to the top surface 301 of the case on the outer surface of the case 30, but this is just one example. For example, in Figure 3, the heat conductive member 44 may be joined to the side surface of the case 30 along the vertical direction Dg on the outer surface of the case 30.

[0103] (4) In each of the embodiments described above, as shown in Figure 3, the electromagnetic relay 10 is positioned such that the axial direction Da of the equipment is perpendicular to the vertical direction Dg when mounted on a vehicle. However, the orientation of the electromagnetic relay 10 when mounted on a vehicle is not limited. For example, the electromagnetic relay 10 may be positioned such that the axial direction Da of the equipment is parallel to the vertical direction Dg. Alternatively, the electromagnetic relay 10 may be positioned such that the upper and lower sides of the vertical direction Dg are reversed relative to Figure 3.

[0104] (5) The present disclosure is not limited to the embodiments described above and can be implemented in various modified forms. Furthermore, the embodiments described above are not unrelated to each other and can be combined as appropriate, except in cases where the combination is clearly impossible.

[0105] Furthermore, it goes without saying that, in each of the above embodiments, the elements constituting the embodiment are not necessarily essential unless explicitly stated to be particularly essential or unless they are clearly considered essential in principle. Also, in each of the above embodiments, when numerical values ​​such as the number, numerical values, quantities, or ranges of the components of the embodiment are mentioned, the embodiment is not limited to those specific numbers unless explicitly stated to be particularly essential or unless it is clearly limited to a specific number in principle. Also, in each of the above embodiments, when the material, shape, positional relationship, etc. of the components are mentioned, the embodiment is not limited to those material, shape, positional relationship, etc. unless explicitly stated or unless it is clearly limited to a specific material, shape, positional relationship, etc. in principle.

Claims

1. An electromagnetic relay comprising: an electromagnetic coil (21) that generates a magnetic force when energized; a first contact portion (14); a second contact portion (121) that moves toward and toward the first contact portion in accordance with the switching of energization and de-energization of the electromagnetic coil, thereby opening and closing the energization path; a case (30) that houses the electromagnetic coil, the first contact portion and the second contact portion inside; and a heat conductive member (44, 45) arranged on the outside of the case, having one surface (441, 451) joined to the case and the other surface (442, 452) provided on the opposite side to the one surface and exposed to the space (30b) around the case, and having a higher thermal conductivity than the case.

2. The electromagnetic relay according to claim 1, wherein the first contact portion has a first contact surface (14a) facing the second contact portion, and the second contact portion has a second contact surface (121a) facing and moving toward and away from the first contact surface, and in a view along the direction normal to the surface (441) (Dg), the first contact surface and the second contact surface fall within the range occupied by the surface.

3. The electromagnetic relay according to claim 1 or 2, wherein the first contact portion and the second contact portion are arranged biased to one side in one direction (Da) within the case, the electromagnetic coil is arranged biased to the other side in the one direction within the case, and the heat conductive member (44) is arranged biased to one side in the one direction relative to the case.

4. The electromagnetic relay according to claim 1 or 2, wherein a plurality of heat conductive members are provided, and the plurality of heat conductive members include a first heat conductive member (44) and a second heat conductive member (45) which are spaced apart from each other and joined to the case, the first contact portion and the second contact portion are arranged biased to one side in one direction (Da) within the case, the electromagnetic coil is arranged biased to the other side in the one direction within the case, the first heat conductive member is arranged biased to one side in the one direction with respect to the case, and the second heat conductive member is arranged on the other side in the one direction with respect to the first heat conductive member.

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